With increasing popularization of power batteries, especially power batteries with high capacity over 10 AH, more and more attentions have been paid to the safety performance of the power batteries.
Typically, a conventional power battery includes a battery cover defining an explosion-proof hole. A rupture film of copper foil is mounted in the explosion-proof hole via welding for sealing the same. When the air pressure in the power battery exceeds a predetermined value, the rupture film of copper foil will break, so as to prevent the power battery from exploding due to excessive air pressure in the power battery.
However, the rupture film of copper foil exposed to the external circumstance and the electrolyte is apt to be corroded by the circumstance and electrolyte. Additionally, the rupture film of copper foil is soldered on the can housing of steel. Due to a potential difference between the copper foil and the steel can housing, electrochemical corrosion may occur.
What is needed, therefore, is to provide an explosion-proof device for use in power batteries, which can prevent the occurrence of electrochemical corrosion of the rupture film.